Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | #ifndef _LINUX_PERCPU_COUNTER_H |
2 | #define _LINUX_PERCPU_COUNTER_H | |
3 | /* | |
4 | * A simple "approximate counter" for use in ext2 and ext3 superblocks. | |
5 | * | |
6 | * WARNING: these things are HUGE. 4 kbytes per counter on 32-way P4. | |
7 | */ | |
8 | ||
1da177e4 LT |
9 | #include <linux/spinlock.h> |
10 | #include <linux/smp.h> | |
c67ad917 | 11 | #include <linux/list.h> |
1da177e4 LT |
12 | #include <linux/threads.h> |
13 | #include <linux/percpu.h> | |
0216bfcf | 14 | #include <linux/types.h> |
1da177e4 LT |
15 | |
16 | #ifdef CONFIG_SMP | |
17 | ||
18 | struct percpu_counter { | |
19 | spinlock_t lock; | |
0216bfcf | 20 | s64 count; |
c67ad917 AM |
21 | #ifdef CONFIG_HOTPLUG_CPU |
22 | struct list_head list; /* All percpu_counters are on a list */ | |
23 | #endif | |
0216bfcf | 24 | s32 *counters; |
1da177e4 LT |
25 | }; |
26 | ||
27 | #if NR_CPUS >= 16 | |
28 | #define FBC_BATCH (NR_CPUS*2) | |
29 | #else | |
30 | #define FBC_BATCH (NR_CPUS*4) | |
31 | #endif | |
32 | ||
833f4077 | 33 | int percpu_counter_init(struct percpu_counter *fbc, s64 amount); |
dc62a30e | 34 | int percpu_counter_init_irq(struct percpu_counter *fbc, s64 amount); |
c67ad917 | 35 | void percpu_counter_destroy(struct percpu_counter *fbc); |
3a587f47 | 36 | void percpu_counter_set(struct percpu_counter *fbc, s64 amount); |
20e89767 | 37 | void __percpu_counter_add(struct percpu_counter *fbc, s64 amount, s32 batch); |
02d21168 | 38 | s64 __percpu_counter_sum(struct percpu_counter *fbc); |
1da177e4 | 39 | |
20e89767 | 40 | static inline void percpu_counter_add(struct percpu_counter *fbc, s64 amount) |
252e0ba6 PZ |
41 | { |
42 | __percpu_counter_add(fbc, amount, FBC_BATCH); | |
43 | } | |
44 | ||
bf1d89c8 PZ |
45 | static inline s64 percpu_counter_sum_positive(struct percpu_counter *fbc) |
46 | { | |
02d21168 | 47 | s64 ret = __percpu_counter_sum(fbc); |
bf1d89c8 PZ |
48 | return ret < 0 ? 0 : ret; |
49 | } | |
50 | ||
51 | static inline s64 percpu_counter_sum(struct percpu_counter *fbc) | |
52 | { | |
02d21168 | 53 | return __percpu_counter_sum(fbc); |
bf1d89c8 PZ |
54 | } |
55 | ||
0216bfcf | 56 | static inline s64 percpu_counter_read(struct percpu_counter *fbc) |
1da177e4 LT |
57 | { |
58 | return fbc->count; | |
59 | } | |
60 | ||
61 | /* | |
62 | * It is possible for the percpu_counter_read() to return a small negative | |
63 | * number for some counter which should never be negative. | |
0216bfcf | 64 | * |
1da177e4 | 65 | */ |
0216bfcf | 66 | static inline s64 percpu_counter_read_positive(struct percpu_counter *fbc) |
1da177e4 | 67 | { |
0216bfcf | 68 | s64 ret = fbc->count; |
1da177e4 LT |
69 | |
70 | barrier(); /* Prevent reloads of fbc->count */ | |
0216bfcf | 71 | if (ret >= 0) |
1da177e4 LT |
72 | return ret; |
73 | return 1; | |
74 | } | |
75 | ||
76 | #else | |
77 | ||
78 | struct percpu_counter { | |
0216bfcf | 79 | s64 count; |
1da177e4 LT |
80 | }; |
81 | ||
833f4077 | 82 | static inline int percpu_counter_init(struct percpu_counter *fbc, s64 amount) |
1da177e4 | 83 | { |
0216bfcf | 84 | fbc->count = amount; |
833f4077 | 85 | return 0; |
1da177e4 LT |
86 | } |
87 | ||
dc62a30e PZ |
88 | #define percpu_counter_init_irq percpu_counter_init |
89 | ||
1da177e4 LT |
90 | static inline void percpu_counter_destroy(struct percpu_counter *fbc) |
91 | { | |
92 | } | |
93 | ||
3a587f47 PZ |
94 | static inline void percpu_counter_set(struct percpu_counter *fbc, s64 amount) |
95 | { | |
96 | fbc->count = amount; | |
97 | } | |
98 | ||
252e0ba6 PZ |
99 | #define __percpu_counter_add(fbc, amount, batch) \ |
100 | percpu_counter_add(fbc, amount) | |
101 | ||
1da177e4 | 102 | static inline void |
20e89767 | 103 | percpu_counter_add(struct percpu_counter *fbc, s64 amount) |
1da177e4 LT |
104 | { |
105 | preempt_disable(); | |
106 | fbc->count += amount; | |
107 | preempt_enable(); | |
108 | } | |
109 | ||
0216bfcf | 110 | static inline s64 percpu_counter_read(struct percpu_counter *fbc) |
1da177e4 LT |
111 | { |
112 | return fbc->count; | |
113 | } | |
114 | ||
0216bfcf | 115 | static inline s64 percpu_counter_read_positive(struct percpu_counter *fbc) |
1da177e4 LT |
116 | { |
117 | return fbc->count; | |
118 | } | |
119 | ||
52d9f3b4 | 120 | static inline s64 percpu_counter_sum_positive(struct percpu_counter *fbc) |
e2bab3d9 AM |
121 | { |
122 | return percpu_counter_read_positive(fbc); | |
123 | } | |
124 | ||
bf1d89c8 PZ |
125 | static inline s64 percpu_counter_sum(struct percpu_counter *fbc) |
126 | { | |
127 | return percpu_counter_read(fbc); | |
128 | } | |
129 | ||
1da177e4 LT |
130 | #endif /* CONFIG_SMP */ |
131 | ||
132 | static inline void percpu_counter_inc(struct percpu_counter *fbc) | |
133 | { | |
aa0dff2d | 134 | percpu_counter_add(fbc, 1); |
1da177e4 LT |
135 | } |
136 | ||
137 | static inline void percpu_counter_dec(struct percpu_counter *fbc) | |
138 | { | |
aa0dff2d | 139 | percpu_counter_add(fbc, -1); |
1da177e4 LT |
140 | } |
141 | ||
3cb4f9fa PZ |
142 | static inline void percpu_counter_sub(struct percpu_counter *fbc, s64 amount) |
143 | { | |
144 | percpu_counter_add(fbc, -amount); | |
145 | } | |
146 | ||
1da177e4 | 147 | #endif /* _LINUX_PERCPU_COUNTER_H */ |